Method and device for concentrating, collimating, and directing light

ABSTRACT

An optical system for light energy concentration may comprise a light concentrator to convert incident light to converging light, a light collimating element to receive the converging light and to reduce an angle of convergence of the converging light, and a light directing element to direct the reduced-angle converging light to a light guide to transmit the directed light.

FIELD

The subject matter disclosed herein relates to an optical system, andmore particularly, to a concentrating photovoltaic system for lightenergy concentration.

BACKGROUND

Though sunlight, the energy source of solar power generation, isvirtually free and abundant, these benefits of sunlight may be offset bya relatively high expense associated with solar power generatingphotovoltaic (PV) cells. Also, corresponding to relatively lowefficiency of such PV cells, a relatively large area may be occupied byPV cells in order to generate a desired amount of electrical power.Accordingly, improvements in efficiency of PV cells may lead to reducedcost for solar power generation and/or increased capacity to generatesolar power.

A concentrating photovoltaic (CPV) system may operate by focusingsunlight via optical elements onto relatively small solar cells toreduce use of costly solar cell materials, for example. CPV technologyis a relatively important method for converting sun energy intoelectricity.

BRIEF DESCRIPTION OF THE DRAWINGS

Non-limiting and non-exhaustive embodiments will be described withreference to the following objects, wherein like reference numeralsrefer to like parts throughout the various objects unless otherwisespecified.

FIG. 1 is a cross-section of a light concentration system, according toan embodiment.

FIG. 2 is a perspective view of a light concentration system, accordingto an embodiment.

FIG. 3 is a cross-section of a portion of a light concentration system,according to an embodiment.

FIG. 4 is a cross-section of a light concentration system, according toanother embodiment.

FIGS. 5-17 are cross-sections of a portion of a light concentrationsystem, according to embodiments.

DETAILED DESCRIPTION

In the following detailed description, numerous specific details are setforth to provide a thorough understanding of claimed subject matter.However, it will be understood by those skilled in the art that claimedsubject matter may be practiced without these specific details. In otherinstances, methods, apparatuses, or systems that would be known by oneof ordinary skill have not been described in detail so as not to obscureclaimed subject matter.

Reference throughout this specification to “one embodiment” or “anembodiment” may mean that a particular feature, structure, orcharacteristic described in connection with a particular embodiment maybe included in at least one embodiment of claimed subject matter. Thus,appearances of the phrase “in one embodiment” or “an embodiment” invarious places throughout this specification are not necessarilyintended to refer to the same embodiment or to any one particularembodiment described. Furthermore, it is to be understood thatparticular features, structures, or characteristics described may becombined in various ways in one or more embodiments. In general, ofcourse, these and other issues may vary with the particular context ofusage. Therefore, the particular context of the description or the usageof these terms may provide helpful guidance regarding inferences to bedrawn for that context.

In an embodiment, a light concentrating system may comprise one or morelight concentrators and a light guiding structure. Such a system mayfocus sunlight, for example, via optical elements onto relatively smallphotovoltaic (PV) cells to convert sun energy into electricity. Lightconcentrators may concentrate incident sun light onto light collimationand/or directing elements. For example, a light collimation and/ordirecting element may collimate concentrated incident light intorelatively small convergence angles and direct the collimated light to alight guiding structure, as described in further detail below. Oneadvantage, among others, provided by performing such collimation may bein that light loss due to decoupling effects may be eliminated orreduced in a light guide structure to transport light to an energyconversion element. In an implementation, an energy conversion elementto convert light into different forms of energy, such as electricity andthermal, for example, may comprise PV cells and/or heat exchangedevices, though claimed subject matter is not so limited.

In an embodiment, one or more light collimating and/or directingelements may be located at intervals external to a light guide so thatthe light collimating and/or directing elements are outside an opticalpath of light travelling in the light guide. Locating light collimatingand/or directing elements in such a way may provide an advantage in thatlight collimating and/or directing elements need not block lighttravelling in a light guide. As a counter example, light collimatingand/or directing elements physically located inside a light guide mayblock portions of light as the light travels along the light guide. Inan implementation, a light guide, such as a rod type of light guide, maybe used to transmit light toward an energy conversion element physicallyand/or optically attached at an end region of the light guide. Lightfrom more than one light concentrator may share the same light guide,though claimed subject matter is not so limited.

In some embodiments, a light collimating and/or directing element may becombined into a single optical element, called a collimation anddirecting element (CDE). For example, a CDE may include at least onesurface located relatively close to a focus point of a lightconcentrator to receive light from the light concentrator.

Light concentrators to collect light over a relatively large area andconcentrate the collected light into a relatively small area maycomprise refractive lenses or a combination of refractive lens (e.g.,compound lenses), and/or Fresnel lenses, just to name a few examples.Such light concentrators may have an associated focal length determininga distance at which light reflecting from (or transmitting through) thelight concentrators may be focused. Additionally, such lightconcentrators may have an associated numerical aperture (N.A.)determining an angle of convergence of a cone of light reflecting fromthe light concentrators. Such an angle of convergence may be describedin terms of an f-number: An f-number (sometimes called focal ratio,f-ratio, f-stop, or relative aperture, for example) may express a focallength divided by an effective aperture diameter of a lightconcentrator, for example. An f-number may comprise a dimensionlessnumber that is a quantitative measure of lens speed or steepness of acone of light, for example. Light concentrators may concentrate light byconverging light at a particular f-number and focusing at a particularfocal length. Optical elements downstream of such light concentratorsmay be arranged based, at least in part, on a focal length and/or N.A.of the light concentrators, for example. An array of such lightconcentrators may comprise one or more light concentrators arranged inany number of possible patterns. In a particular example, such an arraymay comprise light concentrators arranged in rows and columns.

In an embodiment, a method to collect and/or concentrate light maycomprise collecting and focusing incident light onto a light collimatingelement to increase an f-number of the incident light. The method mayfurther comprise steering the f-number-increased light received from thelight collimating element through a light guide, and transmitting thesteered light to an energy converting device via the light guide. In oneimplementation, the light collimating element may perform the lightsteering. In another implementation, a light directing element mayperform the light steering. Increasing an f-number of incident light maybe performed by a curved surface of an optical element. A method mayfurther comprise combining steered light from a plurality of lightcollimating elements.

FIG. 1 is a cross-section of a light concentration system 100, accordingto an embodiment. System 100 may comprise an arrangement of opticalelements such as lenses, mirrors, waveguides, and so on, to concentratelight spread over an area defined by a length 104 into a substantiallysmaller area defined by a length 102, for example. In particular, system100 may include one or more light concentrators 120 to convert incidentlight 150 to a converging cone of light 160. Light concentrator 120 maycomprise a curved mirror, such as a parabolic or spherical reflector,for example. In one implementation, a curved mirror may comprise anytype of material, such as glass, plastic, or metal that may include oneor more reflective coatings. Light 150, which may comprise substantiallyparallel light from the sun, may impinge on a curved surface of lightconcentrator 120 and be reflected into a cone of converging light 160.For example, light 150 reflected from light concentrator 120 may befocused into a cone of light 160 having a particular f-number. Light 160may be focused toward a CDE 130 optically attached to a light guide 110.Such a CDE is described in further detail below. CDE 130 may directlight that it receives into light guide 110, which may carry thedirected light 170 to an energy conversion element 115, for example.Light beams from more than one concentrator may share a light guide.Energy conversion element may comprise one or more devices able toconvert concentrated light to another form of energy, such aselectricity (e.g., via photovoltaic cells) or heat (e.g., via a heatexchanger), just to name a few examples. In a particular implementation,a structure to provide physical support to one or more lightconcentrators 120 and/or light guide 110 may include element 140, whichmay comprise a rigid material to maintain a constant distance betweenlight concentrators 120 and light guide 110, for example.

In an implementation, CDE 130 may be selected to be relatively small toreduce light blocking of incident light 150. However, a size anddimensions of CDE 130 may be sufficiently large to meet designtolerances involving, for example, angle deviation of incident light150, CDE placement or alignment with light concentrator 120, reflectingangles of interior surfaces of the CDE, and/or size of a collimatingportion of the CDE to receive light from light concentrator 120.

FIG. 2 is a perspective view of a light concentration system 200,according to an embodiment. System may be similar to system 100 shown inFIG. 1, for example. Light concentrators 221, 222, and 223 may focuslight into CDEs 231, 232, and 233, respectively. The light concentratorsmay comprise parabolic or spherical reflectors positioned to reflectconverging light to the CDEs. Light received by CDEs 231, 232, 233 maybe coupled into light guide 210. Light guide 210 may comprise any of anumber of types of light guides, such as a rod-type light guide, forexample. Once coupled into light guide 210, light may travel along theinside of light guide 210 by way of total internal reflection, forexample, to reach energy conversion element 215. Of course, such detailsof a light concentration system are merely examples, and claimed subjectmatter is not so limited.

FIG. 3 is a cross-section of a portion of a light concentration system,according to an embodiment 300. CDE 330, optically attached to a lightguide 310, may comprise an optical element including a light collimator335 and a light director 338. Such an optical element may comprisequartz, sapphire, plastic, or other optical material, for example. In aparticular implementation, light collimator 335 may comprise a concavedepression in a surface of CDE 330. Light director 338 may comprise aflat reflective interior surface of CDE 330. In one implementation, aflat reflective interior surface of CDE 330 may reflect light by totalinternal reflection. In another implementation, a flat reflectivesurface of CDE 330 may comprise a reflective coating to reflect lightinternally in CDE 330, for example. In one implementation, light 360entering light collimator 335 may be collimated to produce parallellight 365. In another implementation, light 360 entering lightcollimator 335 may be collimated to produce light 365 having a reducedconvergence angle or increased f-number compared to light 360. For aspecific example, an angle of convergence of light 360 may be about 60.0degrees and an angle of convergence of light 365 may be about 20.0degrees, though claimed subject matter is not so limited. Collimatinglight using a light collimator such as 335, for example, may providebenefits. For example, after collimation, a light path may be moreeasily controlled to avoid or to reduce decoupling effects.

Light director 338 may reflect light 365 at a particular angle based, atleast in part, on an angle 333 between a surface of light guide 310 anda reflecting surface of light director 338. Thus, light director 338 mayreflect light 365 at a particular angle so that the reflected light 370enters light guide 310 at an angle 375 that allows total internalreflection to occur in light guide 310. Light 370 may travel along theinterior of light guide 310 toward an energy converting element, forexample, as shown in FIG. 1.

An optical interface 312 between CDE 330 and light guide 310 maycomprise an adhesive having optical properties to hold CDE 330 to lightguide 310. For example, an epoxy or other adhesive having relativelyhigh transmittance may adhere CDE 330 and light guide 310 to oneanother. In other implementations, CDE 330 may be attached to lightguide 310 by methods other than an adhesive. For example, straps, bolts,or other hardware (not shown) may be used to attach CDE 330 to lightguide 310, though claimed subject matter is not so limited.

FIG. 4 is a cross-section of a light concentration system 400, accordingto another embodiment. Substantially collimated incident light 460transmits through a support structure 405 that physically supportssecondary mirrors 425. Light 460 then impinges on a light concentrator420 comprising a parabolic or spherical reflecting surface, for example.Converging light 465 reflected from light concentrator 420 may bedirected toward secondary mirror 425 that folds a light cone intoaperture 428 in light concentrator 420. After passing through aperture428, light 468 reflected from secondary mirror 425 may impinge on CDE430, which may reduce a cone angle of light 468 and direct the resultinglight into light guide 410. For example, a cone angle of light 468 maybe reduced from about 60.0 to about 20.0 degrees or less. Resultinglight 470 may travel along the interior of light guide 410 toward anenergy converting element 415, for example.

In a particular implementation, a structure to provide physical supportto one or more light concentrators 420, secondary mirrors 425, and/orlight guide 410 may include element 440, which may comprise a rigidmaterial to maintain a constant distance between elements in system 400,for example. Support structure 405 may comprise a piece of glass orother rigid material that is transparent to light.

FIG. 5 is a cross-section of a portion of a light concentration system,according to an embodiment 500. CDE 530, optically attached to a lightguide 510, may comprise an optical element including a light collimator535 and a light director 538. In a particular implementation, lightcollimator 535 may comprise a concave depression in a surface of CDE530. Light director 538 may comprise a curved reflective interiorsurface of CDE 530. Light director 538 may comprise any of a number ofmaterials, such as glass,

Polymethyl methacrylate (PMMA), or polycarbonate (PC), just to name afew examples. In one implementation, a curved reflective interiorsurface of CDE 530 may reflect light by total internal reflection. Inanother implementation, a curved reflective surface of CDE 530 maycomprise a reflective coating to reflect light internally in CDE 530. Inone implementation, light 560 entering light collimator 535 may becollimated to produce parallel light 565. In another implementation,light 560 entering light collimator 535 may be collimated to producelight 565 having a reduced convergence angle or increased f-numbercompared to light 560. Light director 538 may reflect light 565 at aparticular angle based, at least in part, on a shape or curvature of thereflecting surface of light director 538. Thus, light director 538 mayreflect light 565 at a particular angle so that the reflected light 570enters light guide 510 with an angle 575 that allows total internalreflection to occur in light guide 510. Light 570 may travel along theinterior of light guide 510 toward an energy converting element, forexample, as shown in FIG. 1.

FIG. 6 is a cross-section of a portion of a light concentration system,according to an embodiment 600. CDE 630, optically attached to a lightguide 610, may comprise an optical element including a curved surface638, which may implement functions of a light collimator and/or a lightdirector. As such, light 660 impinging on surface 638 may be bothcollimated and directed upon reflection. In one implementation, CDE 630may be integrated with light guide 610 so that CDE 630 and light guide610 comprise a single piece of optical material, for example. In anotherimplementation, CDE 630 and light guide 610 may comprise separate piecesthat are optically attached, for example. In such a case, light guide610 may include at least two opposing plane surfaces, whereintransmitted light may travel from an entry-end surface (e.g., where CDE630 may be located) toward an exit-end surface (e.g., where an energyconversion element may be located). Though claimed subject matter is notso limited, CDE 630 may be larger than light guide 610. Such a curvedsurface 638 may comprise a cylindrical, spherical, parabolic, or freeform shape, just to name a few examples. Surface 638 may comprise any ofa number of materials, such as glass, Polymethyl methacrylate (PMMA), orpolycarbonate (PC), just to name a few examples. In one implementation,curved surface 638 may reflect light by total internal reflection. Inanother implementation, curved surface 638 may comprise a reflectivecoating to reflect light internally in CDE 630. Curved surface 638 mayreflect light 665 at a particular angle based, at least in part, on ashape or curvature of the reflecting surface of curved surface 638 sothat the reflected light 670 enters light guide 610 with an angle thatallows total internal reflection to occur in light guide 610. Light 670may travel along the interior of light guide 610 toward an energyconverting element, for example, as shown in FIG. 1.

FIG. 7 is a cross-section of a portion of a light concentration system,according to an embodiment 700. Embodiment 700 may be similar toembodiment 300 shown in FIG. 3, except that CDE 730 and light guide 710may be separated by a gap 734. Such a gap may be filled with air, forexample. CDE 730 may comprise an optical element including a lightcollimator 735 and a light director 738. Such an optical element maycomprise quartz, sapphire, or other optical material, for example. In aparticular implementation, light collimator 735 may comprise a concavedepression in a surface of CDE 730. Light director 738 may comprise aflat reflective interior surface of CDE 730.

FIG. 8 is a cross-section of a portion of a light concentration system,according to an embodiment 800. A light collimator 830, opticallyattached to a light guide 810, may comprise a concave depression 835 ina surface of light collimator 830. Light director 812 may comprise aflat reflective interior surface at an end region of light guide 810. Inone implementation, such a flat reflective interior surface may reflectlight by total internal reflection. In another implementation, a flatreflective surface of light director 812 may comprise a reflectiveexterior coating to reflect light internally in light guide 810. In oneimplementation, light 860 entering light collimator 830 may becollimated to produce parallel light 865. In another implementation,light 860 entering light collimator 830 may be collimated to producelight 865 having a reduced convergence angle or increased f-numbercompared to light 860. Light director 812 may reflect light 865 at aparticular angle based, at least in part, on an angle 833 of thereflecting surface of light director 812 with respect to a surface oflight guide 810. Thus, light director 812 may reflect light 865 at aparticular angle so that the reflected light 870 travels in light guide810 with an angle that allows total internal reflection to occur inlight guide 810. Light 870 may travel along the interior of light guide810 toward an energy converting element, for example, as shown in FIG.1.

FIG. 9 is a cross-section of a portion of a light concentration system,according to an embodiment 900. A light collimator 930, opticallyattached to a light guide 910, may comprise a convex lens. Lightdirector 912 may comprise a flat reflective interior surface at an endregion of light guide 910. In one implementation, such a flat reflectiveinterior surface may reflect light by total internal reflection. Inanother implementation, a flat reflective surface of light director 912may comprise a reflective exterior coating to reflect light internallyin light guide 910. In one implementation, depending at least in part ona focal length of light collimator 930, light 960 entering lightcollimator 930 may be collimated to produce parallel light 965. Inanother implementation, again depending at least in part on a focallength of light collimator 930, light 960 entering light collimator 930may be collimated to produce light 965 having a reduced convergenceangle or increased f-number compared to light 960. Light director 912may reflect light 965 at a particular angle based, at least in part, onan angle 933 of the reflecting surface of light director 912 withrespect to a surface of light guide 910. Thus, light director 912 mayreflect light 965 at a particular angle so that the reflected light 970travels in light guide 910 with an angle that allows total internalreflection to occur in light guide 910. Light 970 may travel along theinterior of light guide 910 toward an energy converting element, forexample, as shown in FIG. 1.

FIG. 10 is a cross-section of a portion of a light concentration system,according to an embodiment 1000. A light collimator 1030, opticallyattached to a light guide 1010, may comprise a concave lens (e.g., aconcave cylindrical lens). Light director 1012 may comprise a flatreflective interior surface at an end region of light guide 1010. In oneimplementation, such a flat reflective interior surface may reflectlight by total internal reflection. In another implementation, a flatreflective surface of light director 1012 may comprise a reflectiveexterior coating to reflect light internally in light guide 1010. In oneimplementation, depending at least in part on a focal length of lightcollimator 1030, light 1060 entering light collimator 1030 may becollimated to produce parallel light 1065. In another implementation,again depending at least in part on a focal length of light collimator1030, light 1060 entering light collimator 1030 may be collimated toproduce light 1065 having a reduced convergence angle or increasedf-number compared to light 1060. Light director 1012 may reflect light1065 at a particular angle based, at least in part, on an angle 1033 ofthe reflecting surface of light director 1012 with respect to a surfaceof light guide 1010. Thus, light director 1012 may reflect light 1065 ata particular angle so that the reflected light 1070 travels in lightguide 1010 with an angle that allows total internal reflection to occurin light guide 1010. Light 1070 may travel along the interior of lightguide 1010 toward an energy converting element, for example, as shown inFIG. 1.

FIG. 11 is a cross-section of a portion of a light concentration system,according to an embodiment 1100. A light collimator 1130, opticallyattached to a light guide 1110, may comprise a convex lens (e.g., aconvex cylindrical lens). Light director 1112 may comprise a flatreflective interior surface at an end region of light guide 1110. In oneimplementation, such a flat reflective interior surface may reflectlight by total internal reflection. In another implementation, a flatreflective surface of light director 1112 may comprise a reflectiveexterior coating to reflect light internally in light guide 1110. In oneimplementation, depending at least in part on a focal length of lightcollimator 1130, light 1160 entering light collimator 1130 may becollimated to produce parallel light 1165. In another implementation,again depending at least in part on a focal length of light collimator1130, light 1160 entering light collimator 1130 may be collimated toproduce light 1165 having a reduced convergence angle or increasedf-number compared to light 1160. Light director 1112 may reflect light1165 at a particular angle based, at least in part, on an angle 1133 ofthe reflecting surface of light director 1112 with respect to a surfaceof light guide 1110. Thus, light director 1112 may reflect light 1165 ata particular angle so that the reflected light 1170 travels in lightguide 1110 with an angle that allows total internal reflection to occurin light guide 1110. Light 1170 may travel along the interior of lightguide 1110 toward an energy converting element, for example, as shown inFIG. 1.

FIG. 12 is a cross-section of a portion of a light concentration system,according to an embodiment 1200. A light collimator 1230, opticallyattached to a light guide 1210, may comprise a multi-sided prism. Lightdirector 1212 may comprise a flat reflective interior surface at an endregion of light guide 1210. In one implementation, such a flatreflective interior surface may reflect light by total internalreflection. In another implementation, a flat reflective surface oflight director 1212 may comprise a reflective exterior coating toreflect light internally in light guide 1210. In one implementation,depending at least in part on a focal length of light collimator 1230,light 1260 entering light collimator 1230 may be collimated to produceparallel light 1265. In another implementation, again depending at leastin part on a focal length of light collimator 1230, light 1260 enteringlight collimator 1230 may be collimated to produce light 1265 having areduced convergence angle or increased f-number compared to light 1260.Light director 1212 may reflect light 1265 at a particular angle based,at least in part, on an angle 1233 of the reflecting surface of lightdirector 1212 with respect to a surface of light guide 1210. Thus, lightdirector 1212 may reflect light 1265 at a particular angle so that thereflected light 1270 travels in light guide 1210 with an angle thatallows total internal reflection to occur in light guide 1210. Light1270 may travel along the interior of light guide 1210 toward an energyconverting element, for example, as shown in FIG. 1.

FIG. 13 is a cross-section of a portion of a light concentration system,according to an embodiment 1300. A light collimator 1330 may be builtinto light guide 1310. In particular, light collimator 1330 may comprisea concave depression in a surface of light guide 1310. Light director1312 may comprise a prism that is optically attached to a surface oflight guide 1310. In one implementation, light director 1312 maycomprise an optical element that is not integrated with light guide1310. Light 1360 entering light collimator 1330 may be collimated toproduce light 1365 having a reduced convergence angle or increasedf-number compared to light 1360. Light director 1312 may reflect light1365 at a particular angle so that reflected light 1370 travels in lightguide 1310 with an angle that allows total internal reflection to occurin light guide 1310. Light 1370 may travel along the interior of lightguide 1310 toward an energy converting element, for example, as shown inFIG. 1. FIG. 14 is a cross-section of a portion of a light concentrationsystem, according to an embodiment 1400. Surface 1412 may comprise alight collimator and a light director, so that light impinging onsurface 1412 may be both collimated and directed upon reflection.Surface 1412 may comprise a concave-curved reflective interior surfaceof an end region of light guide 1410. In one implementation, such areflective interior surface may reflect light by total internalreflection. In another implementation, a surface 1412 may comprise areflective exterior coating to reflect light internally in light guide1410. In one implementation, light 1460 reflecting from surface 1412 maybe collimated to produce parallel light 1465. In another implementation,light 1460 reflecting from surface 1412 may be collimated to producelight 1465 having a reduced convergence angle or increased f-numbercompared to light 1460. Surface 1412 may reflect light 1460 at aparticular angle based, at least in part, on a shape or curvature ofsurface 1412. Thus, surface 1412 may reflect light 1460 at a particularangle so that the reflected light 1465 travels in light guide 1410 withan angle that allows total internal reflection to occur in light guide1410. Light 1470 may travel along the interior of light guide 1410toward an energy converting element, for example, as shown in FIG. 1.

FIG. 15 is a cross-section of a portion of a light concentration system,according to an embodiment 1500. Surface 1512 may comprise a lightcollimator and a light director, so that light impinging on surface 1512may be both collimated and directed upon reflection. Surface 1512 maycomprise a convex-curved reflective interior surface of an end region oflight guide 1510. In one implementation, such a reflective interiorsurface may reflect light by total internal reflection. In anotherimplementation, a surface 1512 may comprise a reflective exteriorcoating to reflect light internally in light guide 1510. In oneimplementation, light 1560 reflecting from surface 1512 may becollimated to produce parallel light 1565. In another implementation,light 1560 reflecting from surface 1512 may be collimated to producelight 1565 having a reduced convergence angle or increased f-numbercompared to light 1560. Surface 1512 may reflect light 1560 at aparticular angle based, at least in part, on a shape or curvature ofsurface 1512. Thus, surface 1512 may reflect light 1560 at a particularangle so that the reflected light 1565 travels in light guide 1510 withan angle that allows total internal reflection to occur in light guide1510. Light 1570 may travel along the interior of light guide 1510toward an energy converting element, for example, as shown in FIG. 1.

FIG. 16 is a cross-section of a portion of a light concentration system,according to an embodiment 1600. A light collimator 1635 and a lightdirector 1612 may be built into light guide 1610. In particular, lightcollimator 1635 may comprise a concave depression in a surface of lightguide 1610. Light director 1612 may comprise a flat reflective interiorsurface formed by an angular notch in another surface of light guide1610. In one implementation, light 1660 entering light collimator 1635(and light guide 1610) may be collimated to produce parallel light 1665.In another implementation, light 1660 entering light collimator 1635 maybe collimated to produce light 1665 having a reduced convergence angleor increased f-number compared to light 1660. Light director 1612 mayreflect light 1665 at a particular angle so that reflected light 1670travels in light guide 1610 with an angle that allows total internalreflection to occur in light guide 1610. Light 1670 may travel along theinterior of light guide 1610 toward an energy converting element, forexample, as shown in FIG. 1.

FIG. 17 is a cross-section of a portion of a light concentration system,according to an embodiment 1700. A light collimator 1730 may comprise aconvex lens that need not be integrated with light guide 1710. Inparticular, light collimator 1730 may comprise a convex lens opticallycontacting a surface of light guide 1710. Light director 1712 maycomprise a prism that is optically contacting a surface of light guide1710. In one implementation, light director 1712 may comprise an opticalelement that is not integrated with light guide 1710. Light 1760entering light collimator 1730 may be collimated to produce light 1765having a reduced convergence angle or increased f-number compared tolight 1760. Light director 1712 may reflect light 1765 at a particularangle so that reflected light 1770 travels in light guide 1710 with anangle that allows total internal reflection to occur in light guide1710. Light 1770 may travel along the interior of light guide 1710toward an energy converting element, for example, as shown in FIG. 1.One skilled in the art will realize that a virtually unlimited number ofvariations to the above descriptions is possible, and that the examplesand the accompanying figures are merely to illustrate one or moreparticular implementations.

The terms, “and,” “and/or,” and “or” as used herein may include avariety of meanings that also is expected to depend at least in partupon the context in which such terms are used. Typically, “or” as wellas “and/or” if used to associate a list, such as A, B or C, is intendedto mean A, B, and C, here used in the inclusive sense, as well as A, Bor C, here used in the exclusive sense. In addition, the term “one ormore” as used herein may be used to describe any feature, structure, orcharacteristic in the singular or may be used to describe somecombination of features, structures, or characteristics. Though, itshould be noted that this is merely an illustrative example and claimedsubject matter is not limited to this example.

While there has been illustrated and described what are presentlyconsidered to be example embodiments, it will be understood by thoseskilled in the art that various other modifications may be made, andequivalents may be substituted, without departing from claimed subjectmatter. Additionally, many modifications may be made to adapt aparticular situation to the teachings of claimed subject matter withoutdeparting from the central concept described herein. Therefore, it isintended that claimed subject matter not be limited to the particularembodiments disclosed, but that such claimed subject matter may alsoinclude all embodiments falling within the scope of the appended claims,and equivalents thereof.

1. An apparatus comprising: a light concentrator to convert incidentlight to converging light; an optical element comprising a lightcollimating element, a light directing element, and a light guide asseparate or integrated elements of said optical element; said lightcollimating element to receive said converging light and to reduce anangle of convergence of said converging light said light directingelement to re-direct and transfer said reduced-angle converging lightalong a portion of said light guide to transmit said directed light; andwherein said optical element comprises a curved reflective interiorsurface for totally internally reflecting said light at a particularangle based, at least in part, on a curvature of said curved reflectiveinterior surface, such that said total internally reflected light enterssaid light guide at a nonparallel angle that allows total internalreflection to occur in said light guide.
 2. The apparatus of claim 1,wherein said light collimating element includes at least one curvedsurface to perform said reducing the angle of convergence of saidconverging light.
 3. The apparatus of claim 1, wherein said lightcollimating element includes a multi-sided prism to perform saidreducing the angle of convergence of said converging light. 4.(canceled)
 5. The apparatus of claim 1, wherein said light collimatingelement and said light directing element are integrated elements of saidoptical element.
 6. The apparatus of claim 5, wherein said opticalelement comprises at least one curved convex or concave surface toreduce the angle of convergence of said converging light.
 7. Theapparatus of claim 5, further comprising a gap between said light guideand and said integrated light collimating element and light directingelement.
 8. The apparatus of claim 1, wherein said light directingelement and said light guide are integrated elements of said opticalelement.
 9. The apparatus of claim 1, wherein said light collimatingelement and said light guide are integrated elements of said opticalelement.
 10. The apparatus of claim 1, wherein said light collimatingelement, said light directing element, and said light guide areintegrated elements of said optical element.
 11. The apparatus of claim10, wherein said single optical element comprises at least one curvedsurface to reduce the angle of convergence of said converging light. 12.The apparatus of claim 1, wherein said light collimating element is aseparate element of said optical element relative to said light guide.13. The apparatus of claim 1, wherein said light directing element is aseparate element of said optical element relative to said light guide.14. The apparatus of claim 1, wherein said light guide comprises arod-type light guide.
 15. The apparatus of claim 14, wherein said lightguide includes at least two opposing plane surfaces, wherein saidtransmitted light travels from an entry-end surface toward an exit-endsurface.
 16. The apparatus of claim 1, further comprising an energyconversion element to receive said reduced-angle converging light viasaid light guide.
 17. The apparatus of claim 16, wherein said energyconversion element comprises at least one device to convert saidreceived light to other forms of energy.
 18. The apparatus of claim 1,wherein said light concentrator comprises a curved mirror.
 19. Theapparatus of claim 18, wherein said light concentrator further comprisesa secondary curved mirror.
 20. The apparatus of claim 1, wherein saidlight concentrator comprises a refractive lens.
 21. The apparatus ofclaim 1, wherein said light collimating element and light directingelement are integrated in a shaped end of said light guide, and saidshaped end comprises a curved surface.
 22. The apparatus of claim 1,wherein a side of said light guide comprises a notch and another side ofsaid light guide comprises a convex or concave shaped surface, andwherein said notch comprises said light directing element and saidindentation comprises said light collimating element.
 23. The apparatusof claim 1, wherein said light collimating element and said lightdirecting element are to receive said converging light at a focus pointof said light concentrator.
 24. A method comprising: collecting andfocusing incident light from a light concentrator onto a lightcollimating element to increase an f-number of said incident light,wherein said f-number of said incident light represents a quantitativemeasure of a steepness of a cone of said incident light; steering andtransferring said f-number-increased light received from said lightcollimating element via a curved reflective interior surface of a lightdirecting element configured for total internally reflecting saidf-number-increased light at a particular angle based, at least in part,on a curvature of said curved reflective interior surface, saidf-number-increased light entering a light guide at a nonparallel anglethat allows total internal reflection to occur in said light guide; andtransmitting said steered light to an energy converting device via saidlight guide.
 25. (canceled)
 26. (canceled)
 27. The method of claim 24,wherein said increasing said f-number of said incident light isperformed by a curved surface of an optical element.
 28. The method ofclaim 24, further comprising combining steered light from a plurality ofsaid light collimating elements.